方形波電源を用いたセンサおよび伝送線路のノイズ除去法

抄録

Recently the progress in microelectronics has been made in creating complex, highly sensitive, fast processing devices and equipment. Under actual working conditions signals by an instrumentation are inaccurate because of noise. For example, when testing the metal-fatigue of a car's drive-shaft with a strain gage on a real road we can not separate the signal of the strain gage from the noises in the surrounding electromagnetic environment, those from high voltage power lines, electric locomotives, etc.
We proposed three methods of ANC (alternating noise canceling) for the purpose of canceling the noise on the transmission line in an instrumentaion. These methods do not need the reference noise for noise canceling, even if the signal and noise can not be separated in the frequency domain. These three methods use an analog switch to perform the alternating switching of the sensor signals, so the noise added to the sensor can not be canceled.
In this paper, we are proposing a new method of ANC which cancels the noise not only on the transmission line, but also on the sensor. This method uses a rectangular voltage source for switching the polarity of the sensor signal. We have verified the validity of this method by experiments using a strain gage.